The protective membrane of a kind of pressure sensitive adhesive and preparation method thereof and this pressure sensitive adhesive of applicationTechnical field
The present invention relates to a kind of preparation and application thereof of pressure sensitive adhesive, espespecially a kind of is the pressure sensitive adhesive that transparent, 45% solid content, viscosity are little, semi-intercrossing network not containing benezene solvent is pressed and preparation method thereof of gel structure and the protective membrane of using this pressure sensitive adhesive.
Background technology
So-called optical thin film refers at specific plastics sheet or film surface evaporation or applies the last layer chemical material, makes it possess various optical properties.Optical thin film has a variety of, its according to Application Areas or require different, wherein take liquid-crystal display as main application fields.What consist of one of liquid-crystal display important document is backlight source module.And backlight source module mainly is comprised of light source and optical thin film, as reflectance coating (prismatic lens), bright enhancement film, anti-reflection film, diffusion barrier, light guiding plate, polarizing coating etc.Therefore, the quality of optical thin film has determined the inner quality of liquid-crystal display to a great extent.Be quality and the quality of guaranteeing optical thin film, need attach protective membrane in the optically thin pleurodiaphragmatic in terspace sheet course of processing, to prevent from scratching the etch with dust; After process evaporation or coating make its tool optical property, to the optical characteristics layer, need stick protective membrane for preventing scuffing and dust etch again; When this optical thin film is cut, characteristic processing, after being assembled into backlight source module, needing that again the part backlight source module is carried out protective membrane and be wound around protection, to prevent impact damage, moisture immersion, dust etch etc.Be not difficult to find out thus, the backlight source module of a better quality and protective membrane have great relation.
Traditional guard method is to wrap up or the pocket type encapsulation with common plastics film.The method has many deficiencies: the one, and optical thin film can not be effectively protected, and scuffing and dust etch possibility are larger; The 2nd, use inconvenient; The 3rd, the optical characteristics coating is exposed in air, easily oxidized and moisture etch.Therefore, people have developed and applied pressure sensitive adhesive on plastics films, i.e. the pressure sensitive protective membrane.This protective membrane has overcome above three deficiencies, at once covers the last layer sensitive film after namely optical thin film rolls off the production line; This protective membrane of tearing before optical characteristics is processed carries out the optical characteristics processing treatment, at once is covered with layer protecting film after rolling off the production line again; After processing is assembled into backlight source module, then carry out protective membrane winding protection.Due to the effect that pressure sensitive adhesive is arranged, make protective membrane and optical thin film paste, thereby the etch that effectively prevents from scratching and stopping dust, moisture has also prevented the oxidation of optical characteristics layer comprehensively.Therefore, continued up to the main flow that is still at present industry since the protective membrane of this kind pattern from comes out.
Yet along with the continuous progress of technology and the upgrading of end product, also more and more higher to the requirement of optical thin film.As more smart in optical characteristics, thinner; Volume is lighter, less; Functional requirement is more, simpler etc.All are also had higher requirement to protective membrane when optical thin film is required.So, this traditional pressure sensitive protective membrane has also exposed its deficiency:
The one, pressure sensitive adhesive polarity is large, usually reaches 35-38dyne/cm.Therefore, after being attached to Optical Coatings Surface, along with the prolongation of time; the cohesive force increasing degree is large; seem difficult when peeling protective membrane, for picture polycarbonate (PC) plate, more difficult when the large sheet material of the such polarity of polymethylmethacrylate (PMMA) plate peels especially.To split off optical thin film or destroy the optical characteristics coating because cohesive force increases the consequence that causes when peeling protective membrane.
The 2nd, the cold flow characteristic of acrylate pressure-sensitive adhesive increases the contact area of pressure sensitive adhesive and optical thin film, and when also making protective membrane peel, strength can increase.
The 3rd, pressure sensitive adhesive polarity is large, makes it to the bad adaptability that posts of multiple optics thin-film material.Therefore, often can occur that protective membrane is floating to come off.
The 4th, the polarity gene on the pressure sensitive adhesive molecular chain easily and some optical characteristics layer generation chemistry or physical reaction causes the optical characteristics layer to be polluted and reduces its optical characteristics.
The 5th, protective membrane adhesive power adjustability is poor, can not accomplish that different applications or purpose should have different adhesive powers.
Summary of the invention
In order to overcome the deficiency of product under existing background technology, the present invention relates to and provide following two aspect technology and methods:
1. polarity is low, and pressure-sensitive adhesive layer shows inertia, and force of cohesion is large, and surfaces of various materials is all had well posting property, pressure-sensitive adhesive formula and production method thereof that the protective membrane adhesive power is easily transferred.Make pressure sensitive adhesive solution transparent, viscosity is low, not the noxious solvent such as containing benezene.
2. polyethylene (PE) or polypropylene (PP) are base material; under 10000 grades of dustfree environment conditions; online cleaning through coating machine; utilize extraordinary coating machine and reverse coating technique; be coated with in the one side of any base material and be covered with this pressure sensitive adhesive; through heat drying, namely obtain PE or PP protective membrane that optical thin film is used.
The technological method that the present invention takes is:
The protective membrane of a kind of pressure sensitive adhesive and preparation method thereof and this pressure sensitive adhesive of application, pressure-sensitive adhesive formula comprises following component: component one. butyl methacrylate 20-30 part, 2-EHA 20-30 part, the side chain alkyl carbon atoms number of ethyl propenoate 10-15 part is the acrylic compound of 2-8, contain a kind of in formula or two kinds, account for the 60-80% of whole monomers in formula, its Main Function is to provide the adhesive power of pressure sensitive adhesive; Component two. methyl methacrylate 5-10 part, vinyl acetate 5-10 part, the rigidity monomeric compound of Propylene glycol monoacrylate 2-5 part contains a kind of or two kinds in formula, account for the 20-30% of whole monomers in formula, and its Main Function is the force of cohesion that increases pressure sensitive adhesive; Component three. fluorine-silicon modified acrylic ester resin 0-15 part, the modified compound of fluorinated acrylate 0-5 part contains a kind of or two kinds in formula, account for the 5-15% of whole monomers in formula, and its Main Function is to provide low surface tension; Component four. the compound of Viscoat 295 0-1 part or polyethyleneglycol diacrylate 0-1 part, contain a kind ofly in formula, account in formula all 0.2-1% of monomers, its Main Function is to realize the microgel polymerization; Component five. esters solvent is mainly vinyl acetic monomer, N-BUTYL ACETATE, methylcarbonate etc., contains a kind of in formula or two kinds, accounts for the 50-60% of pressure-sensitive adhesive formula, and its Main Function is dilution and takes away heat in polymerization process.Component six. polyether-modified polyisocyanates 0.2-5.0 part, polyester modification polyisocyanic acid junket ester 0.2-5 part, metallo-chelate 0.5-3 part, the linking agent of aziridine cpd 0.1-1 part, contain a kind of in formula, the compound of preferred aliphat kind isocyanate and polyethers or polyester modification, its consumption is take 100 parts of solid propenoic acid ester pressure-sensitives as radix.Its Main Function is to react with the acrylate pressure-sensitive adhesive molecular chain, reaches crosslinked purpose.Preferable methyl butyl acrylate and 2-EHA in pressure-sensitive adhesive formula component one of the present invention; Preferable methyl methyl acrylate and Propylene glycol monoacrylate in component two; Preferred fluorine-silicon modified acrylic ester and fluorinated acrylate in component three; Preferred Viscoat 295 in component four; Preferred vinyl acetic monomer and methylcarbonate in component five; The isocyanate-modified polyether compound of preferred aliphat in component six.
This pressure sensitive adhesive that makes is 45% solid content, containing benezene solvent not, and glue gel-free piece, polarity is low, and is adjustable between 2-10g/25mm by 180 ° of peeling forces of its protective membrane that makes, wettability is splendid, various optical thin films are all had good attaching.
A kind of pressure sensitive adhesive preparation method step is as follows:
1.. take various starting material by above-mentioned formula:
2.. be sequentially added into the starting material except Viscoat 295 and polyether-modified polyisocyanates in reactor, 90 ℃ to 95 ℃ of stirring heating, preferably 92 ℃, condensation, back flow reaction 10 hours.During this time, with 0.5 part of starting material Viscoat 295 with extremely slow speed, be added dropwise in reactor in approximately time-consuming 8 hours, and realized the microgel polymerization, to prepare partial cross-linked pressure sensitive adhesive, after reaction finishes, stopped heating, cooling is filtered, discharging, packing can obtain described pressure sensitive adhesive solution.
And this pressure sensitive adhesive is coated PE or PP protective membrane base material can be used for the protective membrane of optical thin film with making.This protective membrane can be directly used in the processing of optically thin pleurodiaphragmatic in terspace film; the processing of functional optical film; the processing of backlight source module and the processing of all liquid-crystal displays not only can prevent optical thin film by contamination by dust and be scratched, nor the intrinsic optical characteristics of damage optical thin film.
Description of drawings
Fig. 1 is that optical thin film launches sectional schematic diagram
Embodiment
In order to make the technology used in the present invention, means and advantage thereof, now lift preferred embodiment and coordinate accompanying drawing to describe in detail as after, this is not subjected to the restriction of this kind structure only for explanation in patent application.
A kind of pressure sensitive adhesive, formula comprises following component: component one. butyl methacrylate 20-30 part, 2-EHA 20-30 part, the side chain alkyl carbon atoms number of ethyl propenoate 10-15 part is the acrylic compound of 2-8, contain a kind of in formula or two kinds, account for the 60-80% of whole monomers in formula, its Main Function is to provide the adhesive power of pressure sensitive adhesive; Component two. methyl methacrylate 5-10 part, vinyl acetate 5-10 part, the rigidity monomeric compound of Propylene glycol monoacrylate 2-5 part contains a kind of or two kinds in formula, account for the 20-30% of whole monomers in formula, and its Main Function is the force of cohesion that increases pressure sensitive adhesive; Component three. fluorine-silicon modified acrylic ester resin 0-15 part, the modified compound of fluorinated acrylate 0-5 part contains a kind of or two kinds in formula, account for the 5-15% of whole monomers in formula, and its Main Function is to provide low surface tension; Component four. the compound of Viscoat 295 0-1 part or polyethyleneglycol diacrylate 0-1 part, contain a kind ofly in formula, account in formula all 0.2-1% of monomers, its Main Function is to realize the microgel polymerization; Component five. esters solvent is mainly vinyl acetic monomer, N-BUTYL ACETATE, methylcarbonate etc., contains a kind of in formula or two kinds, accounts for the 50-60% of pressure-sensitive adhesive formula, and its Main Function is dilution and takes away heat in polymerization process.Component six. polyether-modified polyisocyanates 0.2-5.0 part, polyester modification polyisocyanic acid junket ester 0.2-5 part, metallo-chelate 0.5-3 part, the linking agent of aziridine cpd 0.1-1 part, contain a kind of in formula, the compound of preferred aliphat kind isocyanate and polyethers or polyester modification, its consumption is take 100 parts of solid propenoic acid ester pressure-sensitives as radix.Its Main Function is to react with the acrylate pressure-sensitive adhesive molecular chain, reaches crosslinked purpose.Preferable methyl butyl acrylate and 2-EHA in pressure-sensitive adhesive formula component one of the present invention; Preferable methyl methyl acrylate and Propylene glycol monoacrylate in component two; Preferred fluorine-silicon modified acrylic ester and fluorinated acrylate in component three; Preferred Viscoat 295 in component four; Preferred vinyl acetic monomer and methylcarbonate in component five; The isocyanate-modified polyether compound of preferred aliphat in component six.
This pressure sensitive adhesive that makes is 45% solid content, containing benezene solvent not, and glue gel-free piece, polarity is low, and is adjustable between 2-10g/25mm by 180 ° of peeling forces of its protective membrane that makes, wettability is splendid, various optical thin films are all had good attaching.
Preparation Example
Form by weight that part to get butyl methacrylate be 30 parts, 2-EHA is 30 parts, methyl methacrylate is 10 parts, Propylene glycol monoacrylate is 5 parts, the fluorine-silicon modified acrylic ester is 11.5 parts, Viscoat 295 is 0.5 part, and vinyl acetic monomer is that 70 parts, methylcarbonate are 52 parts.
At first, be sequentially added in reactor: butyl methacrylate, 2-EHA, methyl methacrylate, Propylene glycol monoacrylate, fluorinated acrylate, vinyl acetic monomer, methylcarbonate;
Then, stir, be heated to 90 ℃ to 95 ℃, preferably 92 ℃, condensation, back flow reaction 10 hours, during, 0.5 part of speed with 8 hours used times of Viscoat 295 is splashed in reactor, realize the microgel polymerization, to prepare partial cross-linked pressure sensitive adhesive.
After reaction finishes, stopped heating, cooling is filtered, and discharging makes pressure sensitive adhesive solution; To every 100 parts of solid part acrylate pressure-sensitive adhesives, add 5 parts of polyether-modified polyisocyanates and carry out secondary crosslinking subsequently, finally make this pressure sensitive adhesive.
The pressure sensitive adhesive of making by this formula and technique is transparent, 45% solid content, and viscosity is little, containing benezene solvent not, glue gel-free piece.With itself and polyether-modified polyisocyanates, the linking agents such as metallo-chelate or aziridines coordinate, and solidify through heat drying, namely form transparently, and force of cohesion is large, and polarity is low, and 180 ° of peeling forces are the pressure-sensitive adhesive layer of little adhesive power of 2-10g/25mm.
This pressure sensitive adhesive has added fluorinated acrylate monomer, monomer that acrylate containing silicone monomer isopolarity is low in formula, so the pressure-sensitive adhesive layer surface polarity is low; Add the monomer of two two keys or three two keys in formula, carried out the Semi-IPN of molecule by the microgel polymerization; Add linking agent before coating, by heat drying, the active group of linking agent and macromolecular chain side chain reacts again, and then has realized the full IPN of molecular level.By above three key problem in technology points, guaranteed that the pressure sensitive adhesive surface polarity is low, guaranteed the force of cohesion of pressure sensitive adhesive, guaranteed little adhesive power of protective membrane.
In addition, the present invention also proposes more than one and states the protective membrane that pressure sensitive adhesive is made, and optical thin film launches sectional schematic diagram such as Fig. 1.Protective membrane base material 2 is polyolefin plastics films; as polyethylene film (PE), polypropylene film (PP), polyvinyl chloride film (PVC), polyester film (PET) etc.; in this example, this protective membrane base material is that thickness is that 50 μ m polyethylene films or thickness are the polypropylene film of 40 μ m, and above-mentioned pressure sensitive adhesive 1 is coated this protective membrane base material 2.In this enforcement, with the extraordinary coating machine that online cleansing double sided cylinder is installed and reverse coating technique, with 5 g/ms, thickness 5 μ m are coated on this protective membrane base material with this pressure sensitive adhesive.
Then, then through heat drying, rolling, the cutting of 100 ℃ of * 3min, namely become the protective membrane that the electronic material of little adhesive power of height smoothness, the transparency, thermotolerance, weathering resistance, wet fastness, resistance to acids and bases is used.
The protective membrane of being used by the optical thin film of manufacturing of the present invention is due to pressure sensitive adhesive adhesion coating interface polarity extremely low (24-26dyne/cm), and pressure sensitive adhesive is inertia, therefore multiple optics thin-film material surface is had good pasting property; Owing to being inertia and low interfacial tension, therefore be covered on the optical thin film material surface after instant peeling force increases slowly or do not increase, so easily peel off; Owing to being inertia or low interfacial tension, therefore be covered on after the optical thin film material surface with the surface chemistry or strong physical reaction occur, so after peeling protective membrane, protected material surface is not contaminated, do not affect its optical characteristics; What take due to pressure-sensitive adhesive of the present invention is the microgel polymerization technique.Therefore guaranteed the force of cohesion of pressure sensitive adhesive, effectively overcome conventional acrylic pressure sensitive adhesive cold flow and become defective, so thoroughly overcome the problem of the easy cull of common acrylate pressure-sensitive adhesive.
The PE or the PP protective membrane that are made by the present invention; can be directly used in the processing of optically thin pleurodiaphragmatic in terspace film; the processing of functional optical film; the processing of backlight source module and the processing of all liquid-crystal displays; the pollution and the scuffing that prevent dust are not only arranged, and do not damage the intrinsic optical characteristics of optical thin film.